Test paper for detecting concentration of phthalic dicarboxaldehyde as well as preparation method and application of test paper

Abstract

The invention discloses phthalic dicarboxaldehyde concentration detection test paper as well as a preparation method and application thereof, and belongs to the technical field of chemical detection. The preparation method comprises the following steps: S1, dissolving a salt compound formed by sulfite, organic amine and acid into water to obtain a soaking solution; s2, immersing filter paper into the soaking solution, taking out the filter paper after full soaking, and drying the filter paper; and S3, pasting the dried filter paper on a non-absorbent substrate to obtain the phthalic dicarboxaldehyde concentration detection test paper: taking a certain volume of phthalic dicarboxaldehyde solution and dropwise adding the phthalic dicarboxaldehyde solution on the test paper during use, and observing the color change of the test paper after a period of time to judge whether the concentration of the phthalic dicarboxaldehyde solution is in an effective range or not. The method disclosed by the invention is simple, the concentration of the effective components is not easy to change in the drying process and the storage process, and the prepared test paper can be used for rapidly and accurately detecting the concentration of the phthalic dicarboxaldehyde.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical detection, and in particular to an o-phthalaldehyde concentration detection test paper and a preparation method and application thereof. Background Art

[0002] O-Phthalaldehyde is a widely used disinfectant. To ensure its effectiveness during use, its concentration needs to be greater than 0.3%, otherwise its disinfection effect cannot be guaranteed. The concentration of o-Phthalaldehyde disinfectant will continue to decrease during storage and use, so it is very necessary to develop an accurate and effective detection method. Existing studies have shown that analytical methods such as titration, ultraviolet-visible spectroscopy, and chromatography can accurately determine the concentration of o-Phthalaldehyde. However, these analytical methods are cumbersome or require the support of relevant instruments. In addition, these methods usually require sample pretreatment and calibration of working curves in advance. These methods are not practical for occasions where the concentration of o-Phthalaldehyde needs to be determined in a timely manner.

[0003] To address these issues, test strips for detecting the concentration of o-phthalaldehyde disinfectants have emerged. These test strips generally work based on a chemical reaction involving o-phthalaldehyde, with the color change after the reaction indicating the concentration of o-phthalaldehyde. These test strips can be generally divided into two types: 1) Using o-phthalaldehyde to react with sulfite to generate a base, the color change of the acid-base indicator then indicates the concentration of o-phthalaldehyde, as described in Chinese patent CN201511015840.6; 2) Using o-phthalaldehyde to react with amino acids or urea to generate a Schiff base, the color of the Schiff base indicating the concentration of o-phthalaldehyde, as described in Chinese patents CN201710339059.7, CN201710339069.0, CN202211313348.7, CN202411527893.5, and CN201710166963.2. Among the reported patents based on test paper for detecting o-phthalaldehyde, there are the following problems: the detection color development time is too long, the composition of the test paper soaking liquid is complex and the cost is high, the test paper production process is cumbersome, and the effective ingredients are easily destroyed during the test paper drying process, which makes the test results prone to misjudgment.

[0004] Therefore, it is of great significance to provide a test paper for detecting o-phthalaldehyde concentration with a simple test paper soaking solution and accurate test results. Summary of the Invention

[0005] In view of the problem that the active ingredients of test strips in the prior art are easily destroyed during the drying process, which leads to misjudgment of the test results, one of the objects of the present invention is to provide a method for preparing test strips for detecting o-phthalaldehyde concentration. The method of the present invention is simple, the active ingredients are not prone to concentration changes during the drying process and storage process, and the prepared test strips can quickly and accurately detect the concentration of o-phthalaldehyde.

[0006] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0007] A method for preparing a test paper for detecting o-phthalaldehyde concentration comprises the following steps:

[0008] S1. The salt compound formed by sulfite and organic amine and acid is dissolved in water to obtain a soaking solution;

[0009] S2. Immerse the filter paper in the soaking solution, remove it after it is fully soaked, and dry it;

[0010] S3. Paste the dried filter paper on a non-absorbent substrate to obtain the o-phthalaldehyde concentration test paper.

[0011] The soaking solution used in the present invention mainly comprises a sulfite (such as sodium sulfite) and a salt compound formed by an organic amine and an acid. The detection principle is that o-phthalaldehyde reacts with sodium sulfite to produce sodium hydroxide. According to the chemical reaction stoichiometry, 1 mol of o-phthalaldehyde reacts with 2 mol of sodium sulfite to produce 2 mol of sodium hydroxide. The generated sodium hydroxide reacts with the salt compound formed by the organic amine and the acid to release free organic amine. The free organic amine can then react with o-phthalaldehyde to produce a colored imine. The key to the present invention is that o-phthalaldehyde does not react with the salt compound formed by the organic amine and the acid. O-phthalaldehyde can react rapidly with sodium sulfite to produce sodium hydroxide. Sodium hydroxide can react with the salt compound formed by the organic amine and the acid to produce free organic amine in the manner of a strong base to a weak base. By controlling the amount of sodium sulfite, if the effective concentration of o-phthalaldehyde in the o-phthalaldehyde disinfectant is lower than the effective value (0.3%), all of the o-phthalaldehyde will react with sodium sulfite. Even if the released sodium hydroxide reacts with the salt compound formed by the organic amine and the acid to release free organic amine, it cannot generate colored imines due to the lack of remaining o-phthalaldehyde. In this case, the o-phthalaldehyde disinfectant is ineffective. When the effective concentration of o-phthalaldehyde in the o-phthalaldehyde disinfectant is higher than the effective value, the remaining o-phthalaldehyde after the reaction with sodium sulfite can react with the free organic amine to generate colored Schiff base. In this case, the o-phthalaldehyde disinfectant is effective.

[0012] The following quantitative calculation further illustrates that the molar mass of o-phthalaldehyde is 134.13 g·mol -1 The molar concentration of o-phthalaldehyde in o-phthalaldehyde disinfectant with a mass percentage concentration of 0.3% is 22.4 mmol·L -1, take 0.1 mL of the above-mentioned o-phthalaldehyde disinfectant and add it dropwise to a certain area of test paper (the amount of sodium sulfite on the test paper is 4.48 μmol), which is equivalent to adding 2.24 μmol of o-phthalaldehyde. 4.48 μmol of sodium sulfite just reacts completely with 2.24 μmol of o-phthalaldehyde. At this time, no matter how much free organic amine is released, no color will appear because all the o-phthalaldehyde has reacted with sodium sulfite. If the mass percentage concentration of o-phthalaldehyde in the o-phthalaldehyde disinfectant is greater than 0.3%, for example, 0.6%, then 0.1 mL of this o-phthalaldehyde disinfectant is added dropwise to a test paper of a certain area (the amount of sodium sulfite on the test paper is 4.48 μmol). This 0.1 mL of o-phthalaldehyde disinfectant contains 4.48 μmol of o-phthalaldehyde. 4.48 μmol of sodium sulfite only consumes 2.24 μmol of o-phthalaldehyde, leaving 2.24 μmol of o-phthalaldehyde. At the same time, 4.48 μmol of sodium hydroxide is generated. These sodium hydroxides react with salt compounds formed by organic amines and acids to release 4.48 μmol of free organic amines (monoamines). These organic amines can react with the remaining o-phthalaldehyde to form colored Schiff bases, indicating that the concentration of o-phthalaldehyde in this o-phthalaldehyde disinfectant is higher than the effective value.

[0013] The key point of the method of the present invention is that an organic amine that can directly react with o-phthalaldehyde is not added to the soaking liquid, but a salt compound formed by the organic amine and an acid is added. In this way, on the one hand, the change of the organic amine concentration can be avoided during the drying process of the test paper. On the other hand, the salt formed by the organic amine and the acid is in a solid state after drying, thereby enhancing the stability of the organic amine during the storage process of the test paper. Moreover, the salt formed by the organic amine and the acid can react with a base generated by the reaction of sulfite and o-phthalaldehyde to release free organic amine, which further reacts with the o-phthalaldehyde remaining after the reaction with sulfite to form a colored imine, thereby indicating the concentration of the o-phthalaldehyde solution.

[0014] The chemical reaction equation involved in the process of detecting the concentration of o-phthalaldehyde in the present invention is as follows:

[0015] .

[0016] Preferably, the sulfite includes at least one of sodium sulfite, potassium sulfite, calcium sulfite, sodium bisulfite, potassium bisulfite, calcium bisulfite, sodium metabisulfite, and sodium dithionite.

[0017] Preferably, the organic amine includes aliphatic amine and / or aromatic amine.

[0018] Preferably, the organic amine includes monoamine and / or diamine.

[0019] More preferably, the organic amine includes at least one of methylamine, ethylamine, propylamine, butylamine, ethylenediamine, propylenediamine, butylenediamine, aniline, o-phenylenediamine, and ethanolamine.

[0020] Preferably, the acid comprises one of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, oxalic acid, lactic acid, citric acid, formic acid, acetic acid, and propionic acid.

[0021] Preferably, the salt compound formed by the organic amine and the acid includes at least one of organic amine hydrochloride, organic amine nitrate, organic amine sulfate, organic amine phosphate, organic amine oxalate, organic amine lactate, organic amine citrate, organic amine formate, organic amine acetate, and organic amine propionate.

[0022] The concentration of sulfite in the soaking solution is greater than 0.06 mol·L -1 .

[0023] The concentration of the salt compound formed by the organic amine and the acid in the soaking solution is greater than 0.04 mol·L -1 .

[0024] Furthermore, when the concentration of sulfite in the soaking solution is greater than 0.12 mol·L -1 The concentration of the salt compound formed by the organic amine and the acid is greater than 0.075 mol·L -1 When the test paper is prepared, it can be used to detect whether the effective concentration of o-phthalaldehyde in the o-phthalaldehyde solution is greater than 0.6%.

[0025] The present invention can realize accurate detection of o-phthalaldehyde solutions with different concentrations by flexibly adjusting the concentrations of sulfite and salt compounds formed by organic amine and acid in the soaking liquid.

[0026] Another object of the present invention is to provide a test paper for detecting o-phthalaldehyde concentration prepared by the method.

[0027] Another object of the present invention is to provide an application of the o-phthalaldehyde concentration detection test paper prepared by the method in detecting o-phthalaldehyde concentration. The application method is as follows: a certain volume of o-phthalaldehyde solution is added dropwise to the detection test paper, and the color change is observed within 1 min to 5 min to determine the concentration range of o-phthalaldehyde.

[0028] In the detection method of the present invention, only a small amount of the o-phthalaldehyde solution to be detected needs to be dripped onto the test paper, which results in low consumption and will not contaminate the o-phthalaldehyde solution to be detected.

[0029] Compared with the prior art, the present invention is beneficial in that:

[0030] (1) The test paper soaking solution of the present invention has simple ingredients and is easy to prepare. Since the organic amine is added in the form of a salt formed with an acid, its concentration is not easily changed during the drying process and is more stable during storage, thereby avoiding the problem of misjudgment of the test results due to changes in the concentration of the active ingredients of the test paper.

[0031] (2) The present invention can achieve accurate detection of o-phthalaldehyde solutions of different concentrations by flexibly adjusting the concentrations of sulfite and salt compounds formed by organic amines and acids in the soaking solution.

[0032] (3) In the detection method of the present invention, only a small amount of the o-phthalaldehyde solution to be detected is dripped onto the test paper, which consumes little and will not contaminate the o-phthalaldehyde solution to be detected.

[0033] (4) The preparation method of the o-phthalaldehyde concentration detection test paper of the present invention is simple and the raw material cost is low. DETAILED DESCRIPTION

[0034] The technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0035] The preparation method of the o-phthalaldehyde concentration detection test paper of the present invention comprises the following steps:

[0036] S1. The salt compound formed by sulfite and organic amine and acid is dissolved in water to obtain a soaking solution;

[0037] S2. Immerse the filter paper in the soaking solution, remove it after it is fully soaked, and dry it;

[0038] S3. Paste the dried filter paper on a non-absorbent substrate to obtain the o-phthalaldehyde concentration test paper.

[0039] In some embodiments, the sulfite is selected from at least one of sodium sulfite, potassium sulfite, calcium sulfite, sodium bisulfite, potassium bisulfite, calcium bisulfite, sodium metabisulfite, and sodium dithionite;

[0040] In some embodiments, the organic amine includes aliphatic amine and / or aromatic amine.

[0041] In other embodiments, the organic amine includes monoamine and / or diamine.

[0042] In some embodiments, the organic amine includes at least one of methylamine, ethylamine, propylamine, butylamine, ethylenediamine, propylenediamine, butylenediamine, aniline, o-phenylenediamine, and ethanolamine.

[0043] In some embodiments, the salt compound formed by the organic amine and the acid includes at least one of organic amine hydrochloride, organic amine nitrate, organic amine sulfate, organic amine phosphate, organic amine oxalate, organic amine lactate, organic amine citrate, organic amine formate, organic amine acetate, and organic amine propionate.

[0044] In some embodiments, the concentration of sulfite in the soaking solution is greater than 0.06 mol·L -1 The concentration of the salt compound formed by the organic amine and the acid in the soaking solution is greater than 0.04 mol·L -1 .

[0045] In other embodiments, the concentration of sulfite in the soaking solution is greater than 0.12 mol·L -1 The concentration of the salt compound formed by the organic amine and the acid is greater than 0.075 mol·L -1 .

[0046] In the present invention, the sulfite can be selected from at least one of sodium sulfite, potassium sulfite, calcium sulfite, sodium bisulfite, potassium bisulfite, calcium bisulfite, sodium metabisulfite, and sodium dithionite, all of which can achieve the effect of accurately detecting the effective concentration of o-phthalaldehyde. In the following examples and comparative examples, only sodium sulfite is selected for illustration.

[0047] In the present invention, the salt compound formed by the organic amine and the acid includes at least one of organic amine hydrochloride, organic amine nitrate, organic amine sulfate, organic amine phosphate, organic amine oxalate, organic amine lactate, organic amine citrate, organic amine formate, organic amine acetate, and organic amine propionate; the organic amine can be selected from aliphatic amines, aromatic amines, monoamines, or diamines. For example, the organic amine can be selected from at least one of methylamine, ethylamine, propylamine, butylamine, ethylenediamine, propylenediamine, butylenediamine, aniline, o-phenylenediamine, and ethanolamine, all of which can achieve the effect of accurately detecting the effective concentration of o-phthalaldehyde. In the following embodiments and comparative examples, only H2NCH2CH2NH2·2HCl, H2NCH2CH2NH2·2HCl, CH3CH2CH2NH2·HCl, and H2NCH2CH2NH2·(COOH)2 are selected as examples.

[0048] Example 1

[0049] This embodiment provides a method for preparing a test paper for detecting o-phthalaldehyde concentration, comprising the following steps:

[0050] S1. Accurately weigh 0.90 g Na₂SO₃ and 1.00 g H₂NCH₂CH₂NH₂·2HCl and dissolve them in 100 mL of ultrapure water to prepare an immersion solution.

[0051] S2. Immerse a 2.5 cm x 8 cm filter paper in the soaking solution for 5 minutes. Remove the paper and dry it in an 80°C oven.

[0052] S3. Paste the dried filter paper onto a non-absorbent substrate to obtain the o-phthalaldehyde concentration test paper.

[0053] Next, we study whether the test paper of this embodiment can accurately indicate the effective concentration of o-phthalaldehyde in the solution.

[0054] Take 0.1 mL of o-phthalaldehyde disinfectant with a known concentration of 0.2% and add it dropwise to the dried test paper. After 2 minutes, the test paper color does not change. The test paper results show that the concentration of o-phthalaldehyde in the o-phthalaldehyde disinfectant is less than 0.3%.

[0055] Take 0.1 mL of o-phthalaldehyde disinfectant with a known concentration of 0.4% and add it dropwise to the dried test paper. After 2 minutes, the test paper will turn yellow. The test paper results show that the concentration of o-phthalaldehyde in the o-phthalaldehyde disinfectant is greater than 0.3%.

[0056] Take 0.1 mL of o-phthalaldehyde disinfectant with a known concentration of 0.6% and add it dropwise to the dried test paper. After 2 minutes, the test paper will turn yellow. The test paper result shows that the concentration of o-phthalaldehyde in the o-phthalaldehyde disinfectant is greater than 0.3%.

[0057] The above results show that the test paper of this embodiment can accurately indicate the concentration of o-phthalaldehyde through color change.

[0058] Example 2

[0059] This embodiment provides a method for preparing a test paper for detecting o-phthalaldehyde concentration, comprising the following steps:

[0060] S1. Accurately weigh 0.90 g Na₂SO₃ and 0.72 g CH₃CH₂CH₂NH₂·HCl and dissolve them in 100 mL of ultrapure water to prepare an immersion solution.

[0061] S2. Immerse a 2.5 cm x 8 cm filter paper in the soaking solution for 5 minutes. Remove the paper and dry it in an 80°C oven.

[0062] S3. Paste the dried filter paper onto a non-absorbent substrate to obtain the o-phthalaldehyde concentration test paper.

[0063] Take 0.1 mL of o-phthalaldehyde disinfectant with a known concentration of 0.6% and add it dropwise to the dried test paper. After 2 minutes, the test paper turns brown, indicating that the concentration of o-phthalaldehyde in the o-phthalaldehyde disinfectant is greater than 0.3%.

[0064] Example 3

[0065] This embodiment provides a method for preparing a test paper for detecting o-phthalaldehyde concentration, comprising the following steps:

[0066] S1. Accurately weigh 0.90 g Na₂SO₃ and 1.13 g H₂NCH₂CH₂NH₂·(COOH)₂ and dissolve them in 100 mL of ultrapure water to prepare an immersion solution.

[0067] S2. Immerse a 2.5 cm x 8 cm filter paper in the soaking solution for 5 minutes. Remove the paper and dry it in an 80°C oven.

[0068] S3. Paste the dried filter paper onto a non-absorbent substrate to obtain the o-phthalaldehyde concentration test paper.

[0069] Take 0.1 mL of o-phthalaldehyde disinfectant with a known concentration of 0.6% and add it dropwise to the dried test paper. After 2 minutes, the test paper will turn yellow. The test paper result shows that the concentration of o-phthalaldehyde in the o-phthalaldehyde disinfectant is greater than 0.3%.

[0070] This shows that the test paper of this embodiment can accurately indicate the concentration of o-phthalaldehyde through color change.

[0071] Comparative Example

[0072] This comparative example provides a method for preparing a test paper for detecting o-phthalaldehyde concentration, comprising the following steps:

[0073] S1. Accurately weigh 0.90 g Na2SO3 and 0.45 g H2NCH2CH2NH2 and dissolve them in 100 mL of ultrapure water to prepare an immersion solution.

[0074] S2. Immerse a 2.5 cm x 8 cm filter paper in the soaking solution for 5 minutes. Remove the paper and dry it in an 80°C oven.

[0075] S3. Paste the dried filter paper onto a non-absorbent substrate to obtain the o-phthalaldehyde concentration test paper.

[0076] Take 0.1 mL of o-phthalaldehyde disinfectant with a known concentration of 0.6% and add it dropwise to the dried test paper. After 2 minutes, observe that there is no obvious change in the color of the test paper.

[0077] This indicates that when organic amines are directly added to the soaking solution, the test paper prepared cannot accurately indicate the concentration of o-phthalaldehyde through color changes, which may be because the organic amines are destroyed during the drying process of the test paper.

[0078] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a test paper for detecting o-phthalaldehyde concentration, characterized in that: The following steps are involved: S1. The salt compound formed by sulfite and organic amine and acid is dissolved in water to obtain a soaking solution; S2. Immerse the filter paper in the soaking solution, remove it after it is fully soaked, and dry it; S3. Paste the dried filter paper on a non-absorbent substrate to obtain the o-phthalaldehyde concentration test paper.

2. The preparation method of a test paper for detecting o-phthalaldehyde concentration according to claim 1, wherein The sulfite includes at least one of sodium sulfite, potassium sulfite, calcium sulfite, sodium bisulfite, potassium bisulfite, calcium bisulfite, sodium metabisulfite, and sodium dithionite.

3. A method for preparing a test paper for detecting o-phthalaldehyde concentration according to claim 1, wherein The organic amine includes aliphatic amine and / or aromatic amine.

4. The preparation method of a test paper for detecting o-phthalaldehyde concentration according to claim 1, wherein The organic amine includes monoamine and / or diamine.

5. A method for preparing a test paper for detecting o-phthalaldehyde concentration according to claim 1, characterized in that: The organic amine includes at least one of methylamine, ethylamine, propylamine, butylamine, ethylenediamine, propylenediamine, butylenediamine, aniline, o-phenylenediamine, and ethanolamine.

6. A preparation method for o-phthalaldehyde concentration detection test paper according to claim 1, characterized in that, The acid includes one of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, oxalic acid, lactic acid, citric acid, formic acid, acetic acid, and propionic acid.

7. A preparation method for o-phthalaldehyde concentration detection test paper according to claim 1, characterized in that, The concentration of sulfite in the soaking solution is greater than 0.06 mol·L -1 .

8. A preparation method for o-phthalaldehyde concentration detection test paper according to claim 1, characterized in that, The concentration of the salt compound formed by the organic amine and the acid in the soaking solution is greater than 0.04 mol·L -1 .

9. the o-phthalaldehyde concentration detection test paper that the method described in any one of claim 1 to 8 prepares.

10. Use of the o-phthalaldehyde concentration detection test paper prepared by the method according to any one of claims 1 to 8 or according to claim 9 in detecting o-phthalaldehyde concentration, characterized in that: The application method is as follows: a certain volume of o-phthalaldehyde solution is added dropwise to the test paper, and the color change is observed within 1 to 5 minutes to determine the concentration range of o-phthalaldehyde.